Lower urinary tract health is an increasingly important health issue, e.g., based on an aging population. Treatment of lower urinary tract conditions is an area of much investigation. Prostate disease, for example, is a significant health risk for males. Diseases of the prostate include prostatitis, benign prostatic hyperplasia (BPH, also known as benign prostatic hypertrophy), and prostatic carcinoma.
Prostatitis is an inflammation of the prostate gland. Types include acute and chronic bacterial forms of prostatitis, and a non-bacterial form. Symptoms can include difficult urination, burning or painful urination, perineal or lower back pain, joint or muscle pain, tender or swollen prostate, blood in the urine, or painful ejaculation. Prostatitis is caused by bacterial infection in many instances, in which case treatment generally includes antimicrobial medication. Noninfectious forms of prostatitis are treated by other means such as administration of an alpha-1-adrenoreceptor antagonist drug to relax the muscle tissue in the prostate and reduce the difficulty in urination.
Benign prostatic hypertrophy (BPH) is a very common disorder affecting an estimated 12 million men in the United States alone. BPH is a chronic condition and is strongly age-related; approximately 50% of men over the age of fifty, 75% of men beyond the age of seventy, and 90% of men over the age of eighty are afflicted with BPH. BPH is a non-cancerous condition characterized by enlargement of the prostate, obstruction of the urethra, and gradual loss of bladder function. Symptoms include difficult urination, frequent urination, incomplete emptying of the bladder, and urgency.
BPH may be treated with a number of therapeutic modalities including surgical and medical methods, depending on severity of symptoms. Treatments range from “watchful waiting” for men with mild symptoms, to medications, to surgical procedures. Examples of useful medications include 5-alpha reductase inhibitors such as Avodart™ and Proscar®.
Transurethral resection of the prostate (TURP) is a preferred surgical method of treating BPH. A typical TURP procedure requires general anesthesia and the placement of a resectoscope in the urethra for removal of multiple small chips of hyperplastic prostatic tissue to relieve the obstruction. Complications from TURP include bleeding, incontinence, retrograde ejaculation, and impotence.
An alternate surgical method for treating BPH is transurethral incision of the prostate (TUIP). In the TUIP procedure, incisions are made in the prostate to relieve pressure and improve flow rate. Incisions are made where the prostate meets the bladder. No tissue is removed in the TUIP procedure. Cutting muscle in this area relaxes the opening to the bladder, which decreases resistance to urine flow from the bladder. A variant of the TUIP procedure in which a laser is used to make the incision is known as transurethral laser incision of the prostate (TULIP).
Other surgical methods used to relieve the symptoms of BPH include methods of promoting necrosis of tissue that blocks the urethra. Hyperthermic methods, for example, use the application of heat to “cook” tissue and kill the cells. The necrosed tissue is gradually absorbed by the body. Several methods of applying heat or causing necrosis have been demonstrated, including direct heat (transurethral needle ablation, or TUNA), microwave (transurethral microwave treatment, or TUMT), ultrasound (high-intensity focused ultrasound, or HIFU), electrical vaporization (transurethral electrical vaporization of the prostate, or TUEVP) and laser ablation (visual laser ablation of the prostate, or VLAP), among others.
Chemical ablation (chemoablation) techniques for promoting prostate tissue necrosis have also been considered. In one chemical ablation technique, absolute ethanol is injected transurethrally into the prostate tissue. This technique is known as transurethral ethanol ablation of the prostate (TEAP). The injected ethanol causes cells of the prostate to burst, killing the cells. The prostate shrinks as the necrosed cells are absorbed.
In addition to prostate conditions, other tissue of the urinary tract can be affected by medical conditions that can be treated by delivery of various therapeutic materials in the form of fluids. Tissues of the bladder (which includes the bladder neck), ureter, kidneys, urethra, as well as the prostate, can be treated by delivery of drugs or other therapeutic agents, such as botox. Therapeutic agents should be delivered with minimized discomfort and procedure time, and with the best degree of accuracy of delivery location and delivery volume as possible. As such, there exists continuing need to provide improved devices for delivering therapeutic fluids to the lower urinary tract, kidneys, ureters, etc. A wide variety of medical treatments are at least partially performed through the delivery and introduction of therapeutic compositions to a treatment location. In home or outpatient settings, typical delivery methods can comprise oral delivery, via liquid or solid forms, as well as a variety of inhalant style devices. In clinical or hospital settings, therapeutic fluids can be injected using needle based or in some minimally invasive procedures. The therapeutic fluid can be delivered through a tubular device such as a catheter or endoscope based systems.
One way in which therapeutic fluids can be delivered internally is through the use a tube-like device configured to provide a jet-injection of the therapeutic fluid at a desired treatment site. Generally, a remote injector is utilized to deliver the therapeutic fluid from an external reservoir located at a proximal end of the tube-like device so such administration can occur at a distal end of the tube-like device. Due to the relatively long travel length of the therapeutic fluid through the tube-like device, the remote injector must generally be capable of pressurizing the therapeutic fluid to pressures exceeding about 200 pounds per square inch, e.g., a pressure of 2,000 psi. In order to accommodate these pressures, the tube-like devices have been fabricated of alloys such as NiTi or stainless steel or with metal-reinforced polymers such as the braided tubes typically found in catheters.
Currently a number of manufacturers make a variety of flexible scopes to navigate the tortuous paths often found in the human body. Scopes such as cytoscopes, endoscopes, ureteroscopes, choledoscopes, and hysteroscopes vary slightly in size and shape by brand. There is advantage to using existing scopes for directing an injection device to a treatment site. Furthermore, there is advantage to controlling the overall size of the injection system and scope so as minimize the invasiveness of the procedure.